1. Field of the Invention
The present invention relates to a device for connecting bony portions, in particular a device for intervertebral connection intended to correct pathological defects of the vertebral column such as lordoses, scolioses, vertebral fractures, discal hernias, etc.
2. Description of the Related Art
Such an intervertebral connection device is described in EP 0 919 199. It comprises a male rod and a female rod intended to be fixed to respective vertebra by pedicular screws. The male rod is mounted in the female rod movably in inclination and in axial translation. The male rod comprises a collar whose convex, peripheral surface constitutes a surface of articulation coacting with an internal cylindrical lateral wall of the female rod during relative movements of the male and female rods. A damping system, comprising two sets of resilient rings disposed about the male rod and on either side of the collar, damp these relative movements.
This device according to EP 0 919 199 has the drawback that the guidance of the male rod in the female rod by the mentioned articulation surface during relative movements of inclination of the rods, can take place only over a limited amplitude, for a given size of the device, because the collar is located between the two sets of resilient rings, which necessarily limits its thickness.